Wipe for use with a germicidal solution

ABSTRACT

An antimicrobial wipe that contains a polymer coating having a synergistic combination of ingredients for providing controlled release of an antimicrobial agent and also good antimicrobial efficacy is provided. One such ingredient is a high molecular weight polyamideamine release agent. Due to the polycationic nature of the release agent, it is able to adhere to the wipe, which is generally formed from fibers having a negative surface charge (e.g., cellulosic fibers). In this manner, the release agent can occupy binding sites on the wipe to inhibit the antimicrobial agent from adhering thereto, thus allowing it to be expressed in the germicidal solution to kill microbes on the desired surface. The adherence of the release agent to the wipe is even further enhanced by crosslinking the polyamideamine to increase its molecular weight, thereby enabling it to form a structural network that physically adheres to the wipe and that blocks the antimicrobial agent from binding thereto. Furthermore, the polyamideamine is amidated so that it contains secondary and/or tertiary amides. A cell permeabilizer is also employed in the polymer coating to enhance the efficacy of the antimicrobial agent during use. More particularly, polycationic materials are particularly useful in permeabilizing the outer cell membrane without adversely impacting the ability of the polyamideamine to release the antimicrobial agent within the wipe.

BACKGROUND OF THE INVENTION

Wipes have been treated with antimicrobial agents for cleaning a widevariety of different surfaces, including hard surfaces, skin, etc. Oneclass of antimicrobial agents that has been employed are water solubleor dispersible cationic antimicrobial actives, such as quaternaryammonium compounds (e.g., benzethonium or benzalkonium salts). Theseantimicrobial agents can be incorporated into an aqueous germicidalsolution that is applied to the wipe during manufacturing (i.e.,pre-moistened wipe) or subsequently added to the wipe by the consumerjust prior to use. One problem, however, is that certain antimicrobialagents can become bound to the polar fibers and are thus generally lesseffective in killing bacteria present on a surface. Another problem isthat the antimicrobial agent becomes readily exhausted after a shortperiod of time such that they only mildly inhibit growth or may only beused for a very limited number of wipes. One attempt to solve thisproblem is described in U.S. Pat. No. 5,421,898. In the '898 patent, therelease of disinfectants from a substrate is controlled by coating thesubstrate with a residue of an aqueous composition of a water solublepolymer and a quaternary disinfectant. The water soluble polymer (e.g.,polyvinyl alcohol) has a weight average molecular weight of 85,000 to186,000 and a degree of hydrolysis of 87% to 89%. Unfortunately,however, coatings of this nature are still not effective enough ininhibiting the absorption of the quaternary disinfectants on polarmaterials, such as cellulosic-based fibrous webs. Furthermore, suchpolymer coatings can also reduce antimicrobial efficacy by leaching outof the wipe during use and blocking the cell walls of the bacteria fromthe antimicrobial agent.

As such, a need currently exists for an antimicrobial wipe that iseffective and able to release a substantial portion of the antimicrobialagent during use.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a wipe foruse with a germicidal solution is disclosed. The wipe comprises afibrous substrate on which is disposed a polymer coating that contains arelease agent and a cell permeabilizer. The release agent includes acrosslinked polyamideamine and the cell permeabilizer includes apolycationic substance. The crosslinked polyamideamine has a weightaverage molecular weight of about 500,000 grams per mole or more, andthe ratio of the weight average molecular weight of the crosslinkedpolyamideamine to the weight average molecular weight of thepolycationic substance is greater than 1.

In accordance with another embodiment of the present invention, a methodfor disinfecting a surface is disclosed. The method comprises contactingthe surface with a wipe impregnated with a germicidal solution so thatthe solution is expressed therefrom. The germicidal solution comprisesan antimicrobial agent. The wipe comprises a fibrous substrate on whichis disposed a polymer coating that contains a release agent and a cellpermeabilizer. The release agent includes a crosslinked polyamideamineand the cell permeabilizer includes a polycationic substance, whereinthe crosslinked polyamideamine has a weight average molecular weight ofabout 500,000 grams per mole or more, and the ratio of the weightaverage molecular weight of the crosslinked polyamideamine to the weightaverage molecular weight of the polycationic substance is greater than1.

Other features and aspects of the present invention are set forth ingreater detail below.

DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS Definitions

As used herein the term “nonwoven web” generally refers to a web havinga structure of individual fibers or threads which are interlaid, but notin an identifiable manner as in a knitted fabric. Examples of suitablenonwoven webs include, but are not limited to, meltblown webs, spunbondwebs, carded webs, wetlaid webs, airlaid webs, etc. The basis weight ofthe nonwoven web may vary, such as from about 5 grams per square meter(“gsm”) to 120 gsm, in some embodiments from about 10 gsm to about 70gsm, and in some embodiments, from about 15 gsm to about 35 gsm.

As used herein, the term “meltblown web” generally refers to a nonwovenweb that is formed by a process in which a molten thermoplastic materialis extruded through a plurality of fine, usually circular, diecapillaries as molten fibers into converging high velocity gas (e.g.air) streams that attenuate the fibers of molten thermoplastic materialto reduce their diameter, which may be to microfiber diameter.Thereafter, the meltblown fibers are carried by the high velocity gasstream and are deposited on a collecting surface to form a web ofrandomly dispersed meltblown fibers. Such a process is disclosed, forexample, in U.S. Pat. No. 3,849,241 to Butin, at al. Generally speaking,meltblown fibers may be microfibers that are substantially continuous ordiscontinuous, generally smaller than 10 microns in diameter, andgenerally tacky when deposited onto a collecting surface.

As used herein, the term “spunbond web” generally refers to a webcontaining small diameter substantially continuous fibers. The fibersare formed by extruding a molten thermoplastic material from a pluralityof fine, usually circular, capillaries of a spinnerette with thediameter of the extruded fibers then being rapidly reduced as by, forexample, eductive drawing and/or other well-known spunbondingmechanisms. The production of spunbond webs is described andillustrated, for example, in U.S. Pat. No. 4,340,563 to Appel, et al.,U.S. Pat. No. 3,692,618 to Dorschner, et al., U.S. Pat. No. 3,802,817 toMatsuki, et al., U.S. Pat. No. 3,338,992 to Kinney, U.S. Pat. No.3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat. No.3,502,538 to Levy, U.S. Pat. No. 3,542,615 to Dobo, et al., and U.S.Pat. No. 5,382,400 to Pike, et al. Spunbond fibers are generally nottacky when they are deposited onto a collecting surface. Spunbond fibersmay sometimes have diameters less than about 40 microns, and are oftenfrom about 5 to about 20 microns.

As used herein, the term “carded web” refers to a web made from staplefibers that are sent through a combing or carding unit, which separatesor breaks apart and aligns the staple fibers in the machine direction toform a generally machine direction-oriented fibrous nonwoven web. Suchfibers are usually obtained in bales and placed in an opener/blender orpicker, which separates the fibers prior to the carding unit. Onceformed, the web may then be bonded by one or more known methods.

As used herein, the term “airlaid web” refers to a web made from bundlesof fibers having typical lengths ranging from about 3 to about 19millimeters (mm). The fibers are separated, entrained in an air supply,and then deposited onto a forming surface, usually with the assistanceof a vacuum supply. Once formed, the web is then bonded by one or moreknown methods.

DETAILED DESCRIPTION

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation, not limitation of theinvention. In fact, it will be apparent to those skilled in the art thatvarious modifications and variations may be made in the presentinvention without departing from the scope or spirit of the invention.For instance, features illustrated or described as part of oneembodiment, may be used on another embodiment to yield a still furtherembodiment. Thus, it is intended that the present invention cover suchmodifications and variations.

Generally speaking, the present invention is directed to anantimicrobial wipe that contains a polymer coating having a synergisticcombination of ingredients for providing controlled release of anantimicrobial agent and also good antimicrobial efficacy. One suchingredient is a high molecular weight polyamideamine release agent. Dueto the polycationic nature of the release agent, it is able to adhere tothe wipe, which is generally formed from fibers having a negativesurface charge (e.g., cellulosic fibers). In this manner, the releaseagent can occupy binding sites on the wipe to inhibit the antimicrobialagent from adhering thereto, thus allowing it to be expressed in thegermicidal solution to kill microbes on the desired surface. Theadherence of the release agent to the wipe is even further enhanced bycrosslinking the polyamideamine to increase its molecular weight,thereby enable it to form a structural network that physically adheresto the wipe and that can block the antimicrobial agent from bindingthereto. Furthermore, the polyamideamine is amidated so that it containssecondary and/or tertiary amides. Without intending to be limited bytheory, it is believed that such amidation can help render the coatingamphiphilic, thus making it is less soluble in an aqueous germicidalsolution and more likely to remain on the wipe during use. While thepolyamideamine is able to adhere to the wipe and help block theantimicrobial agent from binding thereto, it is sometimes possible for asmall amount to leach out into the germicidal solution. Due to therelatively large size of the crosslinked network, any expressedpolyamideamine could potentially restrict access of the antimicrobialagent to the cell walls of bacteria. In this regard, a cellpermeabilizer is also employed in the polymer coating to enhance theefficacy of the antimicrobial agent during use. More particularly,polycationic materials are particularly useful in permeabilizing theouter cell membrane without adversely impacting the ability of thepolyamideamine to release the antimicrobial agent within the wipe.

Various embodiments of the present invention will now be described inmore detail.

I. Polymer Coating

As indicated, the polymer coating of the present invention contains apolyamideamine release agent. Such polymers are generally formed from apolyamine prepolymer that is reacted with a crosslinking agent to form abranched crosslinked network having a variety of different possibleshapes, such as hyperbranched, dendritic, comb-like, and so forth. Theprepolymer may be a polyalkylenepolyamine that contains 3 or more basicnitrogen atoms, and in some embodiments, from 3 to 10 basic nitrogenatoms in the molecule. Examples of suitable polyalkylenepolyaminesinclude, for instance, diethylenetriamine, triethylenetetramine,tetraethylenepentamine, pentaethylenehexamine,diaminopropyleneethylenediamine, trisaminopropylamine,polyethyleneimine, etc., as well as mixtures thereof. In one embodiment,for example, the polyamine is prepared by polymerizing ethyleneimine inthe presence of a catalyst (e.g., carbon dioxide, sodium bisulfite,sulfuric acid, hydrogen peroxide, hydrochloric acid, acetic acid etc).The starting polyethyleneimine may have a weight average molecularweight of from about 300 to about 1,000,000, and in some embodiments,from about 10,000 to about 75,000. The prepolymer may also be apolyamine that is grafted with ethyleneimine, such as described in U.S.Pat. No. 4,144,123 to Scharf, et al., which is incorporated herein inits entirety by reference thereto for all relevant purposes. This may beaccomplished, for example, by allowing ethyleneimine to act on thepolyamine in the presence of acids (e.g., sulfuric acid, phosphoricacid, boron trifluoride etherates, etc.). For example, from 1 to 50, andin some embodiments, from 2 to 25 ethyleneimine units may be grafted perbasic nitrogen group in the polyamine. Other methods for preparingpolyamines are well known in the art and described, for instance, inU.S. Pat. No. 2,182,306 to Ulrich et al.; U.S. Pat. No. 3,033,746 toMayle et al.; U.S. Pat. No. 2,208,095 to Esselmann et al.; U.S. Pat. No.2,806,839 to Crowther; and U.S. Pat. No. 2,553,696 to Wilson.

Amidation of the polyamine may be accomplished in a variety of differentways. For example, amidation of the prepolymer (not crosslinked) mayoccur through condensation of a carboxylic acid with primary orsecondary amine groups of the polyamine. Likewise, crosslinking of anamidated prepolymer and/or unamidated prepolymer may also lead toamidation. In one embodiment, for example, an amidated polyamineprepolymer is initially prepared by a condensation reaction ofpolyalkylenepolyamine with a mono- or multi-functional carboxylic acidor derivative thereof (e.g., carboxylic esters, carboxylic anhydrides,carbonyl halides, or alkyldiketenes) that contains from 1 to 28 carbonatoms, and in some embodiments from 1 to 18, carbon atoms, and which maybe saturated or may contain one or more ethylenically unsaturatednonconjugated double bonds. Suitable mono-functional carboxylic acidsmay include, for instance, formic acid, acetic acid, propionic acid,butyric acid, capric acid, 2-ethylhexanoic acid, benzoic acid, lauricacid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleicacid, arachidic acid, erucic acid, behenic acid, as well as derivativesand mixtures thereof. Suitable multi-functional carboxylic acidslikewise include dicarboxylic acids, such as succinic acid, maleic acid,adipic acid, glutaric acid, suberic acid, sebacic acid, terephthalicacid, etc.; tricarboxylic acids; polycarboxylic acids, as well asderivatives and mixtures thereof. Fatty acid mixtures may, for example,also be employed that are obtained from naturally occurring fattyesters, such as from coconut fat, tallow, soybean oil, linseed oil,rapeseed soil and fish oil. Half-esters of dicarboxylic acids, such asmonomethyl succinate, monoethyl succinate, monomethyl maleate,monomethyl fumarate and mono-tert-butyl maleate, and monoethylenicallyunsaturated carboxylic acids, such as acrylic acid and methacrylic acid,are also suitable.

As a result of amidation, at least a portion of the primary andsecondary nitrogen atoms in the polyalkylenepolyamine form secondary andtertiary amides, respectively. Typically, from about 0.1% to about 90%of the nitrogen atoms capable of undergoing amidation in thepolyalkylenepolyamine are present as amido groups so that the polymerretains at least some NH groups for subsequent reaction, such as with acrosslinking agent. If desired, the polymer may only be “partially”amidated in that the polyalkylenepolyamine undergoes only from about 1%to about 50%, and in some embodiments, from about 2% to about 30%amidation. Such partially amidated condensates are described, forinstance, in U.S. Pat. No. 5,536,370 to Scherr, et al., which isincorporated herein in its entirety by reference thereto for allrelevant purposes.

Crosslinking of the prepolymer (amidated or unamidated) may occur usingany of a variety of different crosslinking agents as is known in theart. Typically, crosslinking agents containing at least two functionalgroups are employed, such as bischlorohydrin or glycidyl ethers,dichloropolyalkylene glycols, dichloroalkanes or vicinal dichloroalkanes(e.g., 1,2-dichloroethane, 1,2-dichloropropane, 1,3-dichloropropane,1,4-dichlorobutane and 1,6-dichlorohexane), epichlorohydrin reactionproducts (e.g., glycerol, ethoxylated or propoxylated glycerols,polyglycerols having from 2 to 15 glycerol units in the molecule andpolyglycerols which may be ethoxylated and/or propoxylated are used aspolyhydric alcohols). Halogen-free crosslinking agents may also beemployed. Such halogen-free crosslinking agents are typicallypolyfunctional (e.g., bifunctional) and include, for instance, (1)ethylene carbonate, propylene carbonate and/or urea, (2)monoethylenically unsaturated carboxylic acids and esters, amides andanhydrides thereof, at least dibasic saturated carboxylic acids orpolycarboxylic acids and the esters, amides and anhydrides derived fromeach of them, such as described above, (3) reaction products ofpolyetherdiamines, alkylenediamines, polyalkylenepolyamines, alkyleneglycols, polyalkylene glycols or mixtures thereof with monoethylenicallyunsaturated carboxylic acids, esters, amides or anhydrides ofmonoethylenically unsaturated carboxylic acids, the reaction productshaving at least two ethylenically unsaturated double bonds, andcarboxamido, carboxyl or ester groups as functional groups, (4) reactionproducts of dicarboxylic esters with ethyleneimine, which reactionproducts contain at least two aziridino groups, and mixtures of thestated crosslinking agents, etc. Such crosslinking agents are describedin more detail in U.S. Pat. No. 6,056,967 to Steuerle, et al., which isincorporated herein in its entirety by reference thereto for allrelevant purposes. Multi-functional carboxylic acids and derivativesthereof, such as described above, are particularly suitable crosslinkingagents. In addition to increasing molecular weight, crosslinking withcertain types of agents (e.g., multi-functional carboxylic acids) mayalso result in amidation of the polymer.

In addition to the modifications referenced above, it should also beunderstood that the polyamideamine may be modified using various othertechniques known in the art. For example, the polyamideamine may bealkoxylated—before, after, and/or during amidation and/or crosslinking.The term “alkoxylation” generally refers to the reaction of an amineswith an alkylene oxide. Suitable alkylene oxides include, for instance,ethylene oxide, propylene oxide, isobutylene oxide, 1,2-butylene oxide,2,3-butylene oxide, pentylene oxide, styrene oxide, as well as mixturesthereof. The ratio of alkylene oxide groups to acidic hydrogen atomsbound to nitrogen in the amine is typically from about 1:1 to about300:1. Techniques for reacting an alkylene oxide with a polyamine areknown in the art, and described in more detail in U.S. Pat. No.6,235,940 to Mohr, et al. and U.S. Pat. No. 7,736,525 to Thankashan, etal., which are incorporated herein in their entirety by referencethereto for all purposes. For example, in certain embodiments, thereaction is carried out in the presence of a basic catalyst, such asalkali metal hydroxides (e.g., lithium hydroxide, sodium hydroxide,potassium hydroxide or cesium hydroxide), alkali metal alkoxides (e.g.,sodium or potassium methoxide, potassium ethoxide, potassiumisopropoxide or potassium tert-butoxide), etc.

Regardless of the particular manner in which it is formed, the resultingcrosslinked polyamidoamine has a relatively high average molecularweight. That is, the weight average molecular weight is typically about500,000 grams per mole or more, in some embodiments about 750,000 gramsper mole or more, and in some embodiments, from about 1,000,000 to about2,000,000 grams per mole, determined using any known technique, such asby light scattering. Such high molecular weight structures are believedto facilitate the ability of the polymer network to become structurallyintegrated with the fibrous substrate, thus enhancing its ability toblock the antimicrobial agent from adhering to the fibrous substrate.

As indicated above, however, the relatively large size of thecrosslinked polyamidoamine network may cause blockage of bacteria cellwalls if any is leached out of the wipe during use. In this regard, thepresent inventors have discovered that a polycationic substance may alsobe employed in the polymer coating to help permeabilize the cell wallsof the bacteria and increase the efficacy of the antimicrobial agent,thereby offsetting any reduction in efficacy that might have beenencountered due to the leaching of the release agent. For example, theouter leaflet of the membrane of Gram-negative bacteria possesses uniqueliposaccharide (“LPS”) molecules that often contribute to the formationof a permeability barrier against hydrophobic substances andmacromolecules. Without intending to be limited by theory, it isbelieved that the polycationic substance can intercalate onto the outermembrane, causing it to weaken and become more susceptible to attack bythe antimicrobial agent.

Generally speaking, the polycationic substance is a polymer having amolecular weight that is low enough so that it does not block thebacteria cells in the manner described above, but also high enough sothat it does not adversely impact the extent to which the polymercoating is able to bind to the wipe. For example, the polycationicsubstance typically has a lower average molecular weight than thepolyamideamine release agent such that the ratio of the averagemolecular weight of the release agent to the average molecular weight ofthe permeabilizer is greater than about 1, in some embodiments fromabout 1.1 to about 3, and in some embodiments, from about 1.2 to about1.8. The weight average molecular weight of the polycationic cellpermeabilizer may, for instance, be from about 200,000 grams per mole toabout 1,500,000 grams per mole, in some embodiments from about 400,000grams per mole to about 1,200,000 grams per mole, and in someembodiments, from about 600,000 to about 1,000,000 grams per mole,determined using any known technique, such as by light scattering.

Suitable polycationic substances for use as a cell permeabilizer mayinclude, for instance, polymyxin, polylysine, protamine, polyamines,etc., as well as derivatives and mixtures thereof. In one particularembodiment, the polyamine may be a crosslinked polyamideamine such asdescribed above. Among other things, the present inventors havediscovered that the use of a crosslinked polyamideamine can possess atleast some of the same benefits as the release agent, but caneffectively function as a permeabilizer due to its lower molecularweight. In fact, in certain embodiments, the cell permeabilizer mayactually be derived from a starting material that is similar to the highmolecular weight polyamideamine described above. This may beaccomplished by subjecting the starting material to a filtration process(e.g., ultrafiltration) that removes a low molecular weight fraction aspermeate and isolates a high molecular weight fraction. The highmolecular weight fraction may serve as the permeabilizer, which has amolecular weight lower than the starting material and within the rangesnoted above. Although not required, the high molecular weight fractionused for the cell permeabilizer may have a narrower molecular weightdistribution than the starting material. For example, the initialstarting material may have a polydispersity index (weight averagemolecular weight divided by the number average molecular weight) ofabout 400 or more, such as determined using conventional techniques(e.g., gel permeation chromatography). The high molecular weightfraction employed as the cell permeabilizer may, however, have apolydispersity index of from 2 to 350, and in some embodiments, fromabout 10 to 300. Various filtration techniques and materials used forsuch separate such polymers are described, for instance, in U.S. Pat.No. 6,056,967 to Steuerle, et al.

The relative amounts of the polycationic cell permeabilizer and thepolyamideamine release agent may vary. In most embodiments, however, itis desired that the cell permeabilizer constitutes a greater weightpercentage of the polymer coating to ensure sufficient antimicrobialefficacy. For instance, the weight ratio of the cell permeabilizer tothe release agent is typically from about 1 to about 20, in someembodiments from about 1.5 to about 15, and in some embodiments, fromabout 2 to about 10. The cell permeabilizer may, for instance,constitute from about 50 wt. % to about 99 wt. %, in some embodimentsfrom about 60 wt% to about 95 wt. %, and in some embodiments, from about70 wt. % to about 90 wt. % of the coating, on a dry basis. Likewise, therelease agent may constitute from about 1 wt. % to about 50 wt. %, insome embodiments from about 5 wt. % to about 40 wt. %, and in someembodiments, from about 10 wt. % to about 30 wt. % of the coating, on adry basis.

II. Wipe Construction

The wipe of the present invention generally contains a fibrous substrateon which the polymer coating is disposed. The polymer coating may beapplied to the substrate during its formation or simply applied onto allor a portion of a surface of the wipe using known techniques, such asprinting, dipping, spraying, melt extruding, coating (e.g., solventcoating, powder coating, brush coating, etc.), foaming, and so forth. Inone embodiment, for example, the coating is applied to the wipe bydipping, spraying, or printing. The coating may be continuous ordiscontinuous over the surface of the wipe. The pattern may, forexample, cover only from about 5% to about 95%, in some embodiments fromabout 10% to about 90%, and in some embodiments, from about 20% to about75% of a surface of the wipe. Such patterned application may havevarious benefits, including enhanced softness and drape, improvedabsorbency, etc.

The ingredients of the polymer coating are typically incorporated into acoating solution prior to being applied to the fibrous substrate. Themanner in which the solution is formed may vary as is known to thoseskilled in the art. In one embodiment, for example, the polyamideaminerelease agent and the polycationic cell permeabilizer may be combinedtogether with a solvent to form a single coating solution that isapplied to the substrate. Alternatively, the release agent and cellpermeabilizer may be applied in separate coating steps so that they arepresent in different layers of a single coating. The solvent(s) used toform the coating formulation may vary, such as water, organic solvents,etc. Because the polyamideamine and polycationic cell permeabilizer aregenerally water soluble, water is often employed. If desired, thesubstrate may be dried at a certain temperature after each coating stepto drive the solvents from the solution. Drying may be accomplishedusing any known technique, such as an oven, drying rolls (e.g.,through-air drying, Yankee dryer), etc. The temperature at which thewipe is dried generally depending on the time period over which it isdried, but is typically at least about 20° C., and in some embodiments,from about 30° C. to about 100° C.

The solids add-on level of the coating is typically from about 0.1% toabout 20%, in some embodiments from about 0.5% to about 15%, and in someembodiments, from about 1% to about 10%. The “solids add-on level” isdetermined by subtracting the weight of the untreated substrate from theweight of the treated substrate (after drying), dividing this calculatedweight by the weight of the untreated substrate, and then multiplying by100%. Lower add-on levels may provide optimum functionality of thesubstrate, while higher add-on levels may provide optimum efficacy.

The nature of the fibrous substrate may vary depending on the intendeduse, and may include materials such as nonwoven webs, knitted fabrics,woven fabrics, cotton fabrics, etc. In one embodiment, for example, thefibrous substrate includes a nonwoven web that contains an absorbentmaterial of sufficient wet strength and absorbency for use in thedesired application. For example, the nonwoven web may include absorbentcellulosic fibers formed by a variety of pulping processes, such askraft pulp, sulfite pulp, thermomechanical pulp, etc. Such pulp fibersmay be high-average fiber length pulp, low-average fiber length pulp, ormixtures thereof. One example of suitable high-average length fluff pulpfibers includes softwood kraft pulp fibers. Softwood kraft pulp fibersare derived from coniferous trees and include pulp fibers such as, butnot limited to, northern, western, and southern softwood species,including redwood, red cedar, hemlock, Douglas fir, true firs, pine(e.g., southern pines), spruce (e.g., black spruce), combinationsthereof, and so forth. Northern softwood kraft pulp fibers may be usedin the present invention. An example of commercially available southernsoftwood kraft pulp fibers suitable for use in the present inventioninclude those available from Weyerhaeuser Company with offices inFederal Way, Washington under the trade designation of “NF-405.” Anothersuitable pulp for use in the present invention is a bleached, sulfatewood pulp containing primarily softwood fibers that is available fromBowater Corp. with offices in Greenville, S.C. under the trade nameCoosAbsorb S pulp. Low-average length fibers may also be used in thepresent invention. An example of suitable low-average length pulp fibersis hardwood kraft pulp fibers. Hardwood kraft pulp fibers are derivedfrom deciduous trees and include pulp fibers such as, but not limitedto, eucalyptus, maple, birch, aspen, etc. Eucalyptus kraft pulp fibersmay be particularly desired to increase softness, enhance brightness,increase opacity, and change the pore structure of the sheet to increaseits wicking ability. Further, other absorbent fibers that may be used inthe present invention, such as abaca, sabai grass, milkweed floss,pineapple leaf, cellulosic esters, cellulosic ethers, cellulosicnitrates, cellulosic acetates, cellulosic acetate butyrates, ethylcellulose, regenerated celluloses (e.g., viscose or rayon), and soforth.

Synthetic thermoplastic fibers may also be employed in the nonwoven web,such as those formed from polyolefins, e.g., polyethylene,polypropylene, polybutylene, etc.; polytetrafluoroethylene; polyesters,e.g., polyethylene terephthalate and so forth; polyvinyl acetate;polyvinyl chloride acetate; polyvinyl butyral; acrylic resins, e.g.,polyacrylate, polymethylacrylate, polymethylmethacrylate, and so forth;polyamides, e.g., nylon; polyvinyl chloride; polyvinylidene chloride;polystyrene; polyvinyl alcohol; polyurethanes; polylactic acid;copolymers thereof; and so forth. Because many synthetic thermoplasticfibers are inherently hydrophobic (i.e., non-wettable), such fibers mayoptionally be rendered more hydrophilic (i.e., wettable) by treatmentwith a surfactant solution before, during, and/or after web formation.Other known methods for increasing wettability may also be employed,such as described in U.S. Pat. No. 5,057,361 to Sayovitz, et al.

When employed, the synthetic fibers may be monocomponent ormulticomponent. Multicomponent fibers are fibers that have been formedfrom at least two polymer components. Such fibers are usually extrudedfrom separate extruders but spun together to form one fiber. Thepolymers of the respective components are usually different from eachother although multicomponent fibers may include separate components ofsimilar or identical polymeric materials. The individual components aretypically arranged in substantially constantly positioned distinct zonesacross the cross-section of the fiber and extend substantially along theentire length of the fiber. The configuration of such fibers may be, forexample, a side-by-side arrangement, a pie arrangement, or any otherarrangement. Multicomponent fibers and methods of making the same aretaught in U.S. Pat. No. 5,108,820 to Kaneko, et al., U.S. Pat. No.4,795,668 to Kruege, et al., U.S. Pat. No. 5,162,074 to Hills, U.S. Pat.No. 5,277,976 to Hogle, et al., U.S. Pat. No. 5,336,552 to Strack, etal., U.S. Pat. No. 5,466,410 to Hills, U.S. Pat. No. 5,069,970 toLargman, et al., U.S. Pat. No. 5,057,368 to Largman, et al., U.S. Pat.No. 5,382,400 to Pike, et al., and U.S. Pat. No. 5,989,004 to Cook. Whenutilized, multicomponent fibers can also be splittable. In fabricatingmulticomponent fibers that are splittable, the individual segments thatcollectively form the unitary multicomponent fiber are contiguous alongthe longitudinal direction of the multicomponent fiber in a manner suchthat one or more segments form part of the outer surface of the unitarymulticomponent fiber. In other words, one or more segments are exposedalong the outer perimeter of the multicomponent fiber. For example,splittable multicomponent fibers and methods for making such fibers aredescribed in U.S. Pat. No. 5,935,883 to Pike and U.S. Pat. No. 6,200,669to Marmon, et al.

If desired, the nonwoven web material may be a composite that contains acombination of synthetic thermoplastic polymer fibers and absorbentfibers, such as polypropylene and pulp fibers. The relative percentagesof such fibers may vary over a wide range depending on the desiredcharacteristics of the nonwoven composite. For example, the nonwovencomposite may contain from about 1 wt. % to about 60 wt. %, in someembodiments from 5 wt. % to about 50 wt. %, and in some embodiments,from about 10 wt. % to about 40 wt. % synthetic polymeric fibers. Thenonwoven composite may likewise contain from about 40 wt. % to about 99wt. %, in some embodiments from 50 wt. % to about 95 wt. %, and in someembodiments, from about 60 wt. % to about 90 wt. % absorbent fibers.

Nonwoven composites may be formed using a variety of known techniques.For example, the nonwoven composite may be a “coform material” thatcontains a mixture or stabilized matrix of thermoplastic fibers and asecond non-thermoplastic material. As an example, coform materials maybe made by a process in which at least one meltblown die head isarranged near a chute through which other materials are added to the webwhile it is forming. Such other materials may include, but are notlimited to, fibrous organic materials such as woody or non-woody pulpsuch as cotton, rayon, recycled paper, pulp fluff and alsosuperabsorbent particles, inorganic and/or organic absorbent materials,treated polymeric staple fibers and so forth. Some examples of suchcoform materials are disclosed in U.S. Pat. No. 4,100,324 to Anderson,et al.; U.S. Pat. No. 5,284,703 to Everhart, et al.; and U.S. Pat. No.5,350,624 to Georger, at al.; which are incorporated herein in theirentirety by reference thereto for all relevant purposes.

Alternatively, the nonwoven composite may be formed be formed byhydraulically entangling fibers and/or filaments with high-pressure jetstreams of water. Hydraulically entangled nonwoven composites of staplelength fibers and continuous filaments are disclosed, for example, inU.S. Pat. No. 3,494,821 to Evans and U.S. Pat. No. 4,144,370 to Boulton,which are incorporated herein in their entirety by reference thereto forall purposes. Hydraulically entangled nonwoven composites of acontinuous filament nonwoven web and pulp fibers are disclosed, forexample, in U.S. Pat. No. 5,284,703 to Everhart, et al. and U.S. Pat.No. 6,315,864 to Anderson, at al., which are incorporated herein intheir entirety by reference thereto for all purposes.

Regardless of the materials or processes utilized to form the wipe, itis typically desired that the basis weight of the wipe be from about 20to about 500 grams per square meter (gsm), and in some embodiments, fromabout 35 to about 350 gsm. Lower basis weight products may beparticularly well suited for use as light duty wipes, while higher basisweight products may be better adapted for use as industrial wipes.

The wipe may assume a variety of shapes, including but not limited to,generally circular, oval, square, rectangular, or irregularly shaped.Each individual wipe may be arranged in a folded configuration andstacked one on top of the other to provide a stack of wet wipes. Suchfolded configurations are well known to those skilled in the art andinclude c-folded, z-folded, quarter-folded configurations and so forth.For example, the wipe may have an unfolded length of from about 2.0 toabout 80.0 centimeters, and in some embodiments, from about 10.0 toabout 25.0 centimeters. The wipes may likewise have an unfolded width offrom about 2.0 to about 80.0 centimeters, and in some embodiments, fromabout 10.0 to about 25.0 centimeters. The stack of folded wipes may beplaced in the interior of a container, such as a plastic tub, to providea package of wipes for eventual sale to the consumer. Alternatively, thewipes may include a continuous strip of material which has perforationsbetween each wipe and which may be arranged in a stack or wound into aroll for dispensing. Various suitable dispensers, containers, andsystems for delivering wipes are described in U.S. Pat. No. 5,785,179 toBuczwinski, et al.; U.S. Pat. No. 5,964,351 to Zander; U.S. Pat. No.6,030,331 to Zander; U.S. Pat. No. 6,158,614 to Haynes, et al.; U.S.Pat. No. 6,269,969 to Huang, et al.; U.S. Pat. No. 6,269,970 to Huang,et al.; and U.S. Pat. No. 6,273,359 to Newman, et al.

III. Germicidal Solution

To impart the desired antimicrobial properties, a germicidal solution isalso applied to the polymer-coated wipe. The solution may be applied tothe wipe during manufacturing so that the wipe is “premoistened” priorto or during use. Alternatively, the wipe may be supplied as a “dry”wipe, and the germicidal solution can simply be added thereto by aconsumer, user, etc., prior to or during use.

The wipe may be applied with a germicidal solution by any suitablemethod known in the art, such as spraying, dipping, saturating,impregnating, brush coating and so forth. The amount of the germicidalsolution that may be added to the wipe may vary depending upon the typeof wipe material utilized, the type of container used to store thewipes, the nature of the germicidal solution, and the desired end use ofthe wipes. Generally, each wipe contains from about 150 wt. % to about600 wt. % and desirably from about 300 wt. % to about 500 wt. % of thegermicidal solution based on the dry weight of the wipe. In embodimentsin which the wipe is made from a relatively absorbent substrate (e.g.,fabrics containing pulp fibers), the amount of the germicidal solutioncontained within the wipe can be from about 300 wt. % to about 600 wt. %and desirably about 500 wt. % based on the dry weight of the wipe. Inembodiments in which the wipe is made from a relatively non-absorbentsubstrate (e.g., polypropylene meltblown or spunbonded fabric), theamount of the germicidal solution contained within the wipe can be fromabout 150 wt. % to about 500 wt. % and desirably about 400 wt. % basedon the dry weight of the wipe.

Regardless of the manner in which it is applied, however, the germicidalsolution generally includes an antimicrobial agent. Any antimicrobialagent that is capable of killing and/or inhibiting the growth ofmicroorganisms (e.g., gram negative and/or positive bacteria) can beutilized in the present invention. In one particular embodiment, theantimicrobial agent includes at least one quaternary ammonium compoundhaving the following formula:

wherein,

R₁, R₂, R₃, and R₄ are independently selected from the group consistingof H, C₁-C₃₀ alkyl, C₁-C₃₀ alkenyl, C₁-C₃₀ alkylethoxy, C₁-C₃₀alkylphenolethoxy, etc.; and

A is selected from the group consisting of halogens (e.g., chlorine,bromine, fluorine, etc.); methosulfates, phosphates, etc. For instance,some suitable quaternary ammonium compounds that may be used in presentinvention include, but are not limited to, benzalkonium chloride (BZK)or other benzalkonium halides, benzethonium chloride or otherbenzethonium halides, cetylpyridinium chloride, dequalinium chloride,N-myristyl-N-methyl-morpholinium methyl sulfate,poly-N-3-(dimethylammonio)propyl-N-3-(ethyleneoxyethelenedimethylammonio)propylurea dichloride,alpha-4-1-tris(2-hydroxyethyl)ammo-niumchloride-2-butenyl-omega-tris(2-hydroxyethyl)ammonium chloride,polyoxyethylene (dimethyliminio)ethylene(dimethyliminio)-ethylenedichloride.

In some embodiments, quaternary ammonium halide compounds having thefollowing formula may be employed:

wherein,

R is a C₈-C₁₈ alkyl group; and

A is a halogen atom, such as chlorine, bromine, fluorine, etc. Onecommercially available example of an antimicrobial agent that includessuch a quaternary ammonium compound is available under the trade nameBARDAC® 208M from Lonza, Inc., Allendale, N.J. Specifically, BARDAC®208M contains a blend of alkyl dimethyl benzyl ammonium chlorides. Othercommercially available examples of suitable quaternary ammoniumcompounds are believed to include BARDAC® 2050 and BARDAC® 2080 (basedon dialkyl(C₈-C₁₀)dimethyl ammonium chloride); BARDAC® 2250 and BARDAC®2280 (didecyl dimethyl ammonium chloride); BARDAC® LF and BARDAC® LF 80(based on dioctyl dimethyl ammonium chloride); BARQUAT® MB-50 andBARQUAT® MB-80 (based on alkyl dimethyl benzyl ammonium chloride);BARQUAT® MX-50 and BARQUAT® MX-80 (based on alkyl dimethyl benzylammonium chloride); BARQUAT® OJ-50 and BARQUAT® OJ-80 (based on alkyldimethyl benzyl ammonium chloride); BARQUAT® 4250, BARQUAT® 4280,BARQUAT® 4250Z, and BARQUAT® 4280Z (based on alkyl dimethyl benzylammonium chloride and/or alkyl dimethyl ethyl benzyl ammonium chloride);and BARQUAT® MS-100 (based on myristyl dimethyl benzyl ammoniumchloride), which are available from Lonza, Inc. Suitable germicidalsolutions containing such compounds are also commercially available,such as VIREX® II 128, which is sold by Diversey, Inc. and containsN-alkyl dimethyl benzyl ammonium chloride, didecyl dimethyl ammoniumchloride, and ethanol. Still other solutions of blended quaternaryammonium compounds are available from Ecolab, Inc. of St. Paul, Minn.under the trade designation OASIS™ (e.g., OASIS™ 146).

In addition to quaternary ammonium compounds, other antimicrobial agentsmay also be utilized in the present invention. For instance, somesuitable antimicrobial agents that may be utilized include, but are notlimited to, alcohols, halogenated diphenyl ethers like2,4,4′-trichloro-2′-hydroxydiphenyl ether (Triclosan® or TCS) or2,2′-dihydroxy-5,5′-dibromo-diphenyl ether; phenolic compounds likephenoxyethanol, phenoxy propanol, phenoxyisopropanol,para-chloro-meta-xylenol (PCMX), etc.; bisphenolic compounds, such as2,2′-methylene bis(4-chlorophenol), 2,2′-methylenebis(3,4,6-trichlorophenol), 2,2′-methylene bis(4-chloro-6-bromophenol),bis(2-hydroxy-3,5-dichlorophenyl)sulphide, andbis(2-hydroxy-5-chlorobenzy-l)sulphide; halogenated carbanilides (e.g.,3,4,4′-trichlorocarbanilides (Triclocarban® or TOG); benzyl alcohols;chlorhexidine; chlorhexidine gluconate; and chlorhexidine hydrochloride.Other suitable antimicrobial agents are described in WO 96/06152; WO96106153; and U.S. Pat. No. 6,201,695 to Beerse, et al. In addition,various other antimicrobial agents are set forth in Title 21, Section178.010 of the United States Code of Federal Regulations (C.F.R.).

The amount of the antimicrobial agent utilized in the germicidalsolution can generally vary depending on the relative amounts of theother components present within the solution. Typically, theantimicrobial agent is present in the solution in an amount from about0.01% to about 20% by weight, in some embodiments from about 0.1% toabout 15% by weight, and in some embodiments, from about 0.2% to about10% by weight of the germicidal solution.

It is usually desired that an aqueous solvent (e.g., water) is employedas the carrier of the germicidal solution, although it should beunderstood that other suitable carriers are also contemplated in thepresent invention. For example, water is typically present in thegermicidal solution in an amount from about 10 wt. % to about 99 wt. %,in some embodiments from about 40 wt. % to about 95 wt. %, and in someembodiments, from about 60 wt. % to about 94 wt. % of the germicidalsolution.

In some instances, the germicidal solution of the present invention mayalso include one or more non-aqueous solvents. Although not required,non-aqueous solvents can sometimes aid in dissolving certain components(e.g., antimicrobial agent) of the germicidal solution. Moreover, insome instances, the non-aqueous solvent may also enhance theantimicrobial efficacy of the germicidal solution. Examples of somesuitable non-aqueous solvents include, but are not limited to, glycols,such as propylene glycol, butylene glycol, triethylene glycol, hexyleneglycol, polyethylene glycols, ethoxydiglycol, and dipropyleneglycol;alcohols, such as ethanol, n-propanol, and isopropanol; triglycerides;ethyl acetate; acetone; triacetin; and combinations thereof. Especiallydesired solvent combinations include a glycol, particularly hexyleneand/or propylene glycol, and one or more lower alcohols, particularlyisopropanol, n-propanol, and/or ethanol. The amount of non-aqueoussolvents utilized in the germicidal solution can generally varydepending on the relative amounts of the other components present withinthe solution. When utilized, non-aqueous solvents are typically presentin the solution in an amount from about 0.001% to about 30% by weight,in some embodiments from about 0,1 to about 15% by weight, and in someembodiments, from about 1% to about 15% by weight of the germicidalsolution.

The germicidal solution may optionally include additional ingredients toimpart various benefits. For instance, the germicidal solution may alsoemploy surfactants to enhance the wettability of the composition on asubstrate, to help emulsify or dissolve other ingredients, to increaseviscosity, etc. When utilized, the amount of the surfactants utilized inthe germicidal solution may generally vary depending on the relativeamounts of the other components present within the composition. Thesurfactants may include nonionic surfactants, such as ethoxylatedalkylphenols, ethoxylated and propoxylated fatty alcohols, ethyleneoxide-propylene oxide block copolymers, ethoxylated esters of fatty(C₈-C₁₈) acids, condensation products of ethylene oxide with long chainamines or amides, condensation products of ethylene oxide with alcohols,and mixtures thereof. Various specific examples of suitable nonionicsurfactants include, but are not limited to, methyl gluceth-10, PEG-20methyl glucose distearate, PEG-20 methyl glucose sesquistearate, C₁₁₋₁₅pareth-20, ceteth-8, ceteth-12, dodoxynol-12, laureth-15, PEG-20 castoroil, polysorbate 20, steareth-20, polyoxyethylene-10 cetyl ether,polyoxyethylene-10 stearyl ether, polyoxyethylene-20 cetyl ether,polyoxyethylene-10 oleyl ether, polyoxyethylene-20 oleyl ether, anethoxylated nonylphenol, ethoxylated octylphenol, ethoxylateddodecylphenol, or ethoxylated fatty (C₆-C₂₂) alcohol, including 3 to 20ethylene oxide moieties, polyoxyethylene-20 isohexadecyl ether,polyoxyethylene-23 glycerol laurate, polyoxy-ethylene-20 glycerylstearate, PPG-10 methyl glucose ether, PPG-20 methyl glucose ether,polyoxyethylene-20 sorbitan monoesters, polyoxyethylene-80 castor oil,polyoxyethylene-15 tridecyl ether, polyoxy-ethylene-6 tridecyl ether,laureth-2, laureth-3, laureth-4, PEG-3 castor oil, PEG 600 dioleate, PEG400 dioleate, and mixtures thereof.

Ionic surfactants (i.e., anionic, cationic, or amphoteric surfactants)may also be employed in the germicidal solution. For instance, one classof amphoteric surfactants that may be used are derivatives of secondaryand tertiary amines having aliphatic radicals that are straight chain orbranched, wherein one of the aliphatic substituents contains from about8 to 18 carbon atoms and at least one of the aliphatic substituentscontains an anionic water-solubilizing group, such as a carboxy,sulfonate, or sulfate group. Some examples of amphoteric surfactantsinclude, but are not limited to, sodium 3-(dodecylamino)propionate,sodium 3-(dodecylamino)-propane-1-sulfonate, sodium2-(dodecylamino)ethyl sulfate, sodium 2-(dimethylamino)octadecanoate,disodium 3-(N-carboxymethyl-dodecylamino)propane-1-sulfonate, disodiumoctadecyliminodiacetate, sodium 1-carboxymethyl-2-undecylimidazole, andsodium N,N-bis(2-hydroxyethyl)-2-sulfato-3-dodecoxypropylamine.Additional classes of amphoteric surfactants include phosphobetaines andthe phosphitaines. For instance, some examples of such amphotericsurfactants include, but are not limited to, sodium coconut N-methyltaurate, sodium oleyl N-methyl taurate, sodium tall oil acid N-methyltaurate, sodium palmitoyl N-methyl taurate,cocodimethylcarboxymethylbetaine, lauryidimethylcarboxymethylbetaine,lauryldimethylcarboxyethylbetaine, cetyldimethylcarboxymethylbetaine,lauryl-bis-(2-hydroxyethyl)-carboxymethylbetaine,oleyldimethylgammacarboxypropylbetaine,lauryl-bis-(2-hydroxypropyl)-carboxyethylbetaine,cocoamidodimethylpropylsultaine, stearylamidod imethyl propylsultaine,laurylamido-bis-(2-hydroxyethyl)-propylsultaine, di-sodium oleamidePEG-2 sulfosuccinate, TEA oleamido PEG-2 sulfosuccinate, disodiumoleamide MEA sulfosuccinate, disodium oleamide MIPA sulfosuccinate,disodium ricinoleamide MEA sulfosuccinate, disodium undecylenamide MEAsulfosuccinate, disodium wheat germamido MEA sulfosuccinate, disodiumwheat germamido PEG-2 sulfosuccinate, disodium isostearamideo MEAsulfosuccinate, cocoamphoglycinate, cocoamphocarboxyglycinate,lauroamphoglycinate, lauroamphocarboxyglycinate,capryloamphocarboxyglycinate, cocoamphopropionate,cocoamphocarboxypropionate, lauroamphocarboxypropionate,capryloamphocarboxypropionate, dihydroxyethyl tallow glycinate,cocoamido disodium 3-hydroxypropyl phosphobetaine, lauric myristic amidodisodium 3-hydroxypropyl phosphobetaine, lauric myristic amido glycerylphosphobetaine, lauric myristic amido carboxy disodium 3-hydroxypropylphosphobetaine, cocoamido propyl monosodium phosphitaine, lauricmyristic amido propyl monosodium phosphitaine, and mixtures thereof.

Moreover, exemplary anionic surfactants include alkyl sulfates, alkylether sulfates, alkyl ether sulfonates, sulfate esters of analkylphenoxy polyoxyethylene ethanol, α-olefin sulfonates, β-alkoxyalkane sulfonates, alkyl sulfonates, alkyl monoglyceride sulfates, alkylmonoglyceride sulfonates, alkyl carbonates, alkyl ether carboxylates,fatty acids, sulfosuccinates, sarcosinates, octoxynol or nonoxynolphosphates, taurates, fatty taurides, fatty acid amide polyoxyethylenesulfates, isethionates, or mixtures thereof. Particular examples ofanionic surfactants include, but are not limited to, C₈-C₁₈ alkylsulfates, C₈-C₁₈ fatty acid salts, C₈-C₁₈ alkyl ether sulfates havingone or two moles of ethoxylation, C₈-C₁₈ alkamine oxides, C₈-C₁₈ alkoylsarcosinates, C₈-C₁₈ sulfoacetates, C₈-C₁₈ sulfosuccinates, C₈-C₁₈ alkyldiphenyl oxide disulfonates, C₈-C₁₈ alkyl carbonates, C₈-C₁₈alpha-olefin sulfonates, methyl ester sulfonates, and blends thereof.The C₈-C₁₈ alkyl group may be straight chain (e.g., lauryl) or branched(e.g., 2-ethylhexyl). The cation of the anionic surfactant may be analkali metal (e.g., sodium or potassium), ammonium, C₁-C₄ alkylammonium(e.g., mono-, di-, tri-), or C₁-C₃ alkanolammonium (e.g., mono-, di-,tri). More specifically, such anionic surfactants may include, but arenot limited to, lauryl sulfates, octyl sulfates, 2-ethylhexyl sulfates,lauramine oxide, decyl sulfates, tridecyl sulfates, cocoates, lauroylsarcosinates, lauryl sulfosuccinates, linear C₁₀ diphenyl oxidedisulfonates, lauryl sulfosuccinates, lauryl ether sulfates (1 and 2moles ethylene oxide), myristyl sulfates, oleates, stearates, tallates,ricinoleates, cetyl sulfates, and similar surfactants.

The germicidal solution may also contain a preservative or preservativesystem to inhibit the growth of microorganisms over an extended periodof time. Suitable preservatives may include, for instance, alkanols,disodium EDTA (ethylenediamine tetraacetate), EDTA salts, EDTA fattyacid conjugates, isothiazolinone, benzoic esters (parabens) (e.g.,methylparaben, propylparaben, butylparaben, ethylparaben,isopropylparaben, isobutylparaben, benzylparaben, sodium methylparaben,and sodium propylparaben), benzoic acid, propylene glycols, sorbates,urea derivatives (e.g., diazolindinyl urea), and so forth. Othersuitable preservatives include those sold by Sutton Labs, such as“Germall 115” (amidazolidinyl urea), “Germall II” (diazolidinyl urea),and “Germall Plus” (diazolidinyl urea and iodopropynyl butylcarbonate).Another suitable preservative is Kathon CG®, which is a mixture ofmethylchloroisothiazolinone and methylisothiazolinone available fromRohm & Haas; Mackstat H 66 (available from Mcintyre Group, Chicago,Ill.). Still another suitable preservative system is a combination of56% propylene glycol, 30% diazolidinyl urea, 11% methylparaben, and 3%propylparaben available under the name GERMABEN® II from InternationalSpecialty Products of Wayne, N.J.

The pH of the germicidal solution may also be controlled within a rangethat is considered more biocompatible. For instance, it is typicallydesired that the pH is within a range of from about 5 to about 8, and insome embodiments, from about 6 to about 7. Various pH modifiers may beutilized in the germicidal solution to achieve the desired pH level.Some examples of pH modifiers that may be used in the present inventioninclude, but are not limited to, mineral acids, sulfonic acids (e.g.,2-[N-morpholino]ethane sulfonic acid), carboxylic acids, and polymericacids. Specific examples of suitable mineral acids are hydrochloricacid, nitric acid, phosphoric acid, and sulfuric acid. Specific examplesof suitable carboxylic acids are lactic acid, acetic acid, citric acid,glycolic acid, maleic acid, gallic acid, malic acid, succinic acid,glutaric acid, benzoic acid, malonic acid, salicylic acid, gluconicacid, and mixtures thereof. Specific examples of suitable polymericacids include straight-chain poly(acrylic) acid and its copolymers(e.g., maleic-acrylic, sulfonic-acrylic, and styrene-acryliccopolymers), cross-linked polyacrylic acids having a molecular weight ofless than about 250,000, poly(methacrylic) acid, and naturally occurringpolymeric acids such as carageenic acid, carboxymethyl cellulose, andalginic acid. Basic pH modifiers may also be used in some embodiments ofthe present invention to provide a higher pH value. Suitable pHmodifiers may include, but are not limited to, ammonia; mono-, di-, andtri-alkyl amines; mono-, di-, and tri-alkanolamines; alkali metal andalkaline earth metal hydroxides; alkali metal and alkaline earth metalsilicates; and mixtures thereof. Specific examples of basic pH modifiersare ammonia; sodium, potassium, and lithium hydroxide; sodium,potassium, and lithium meta silicates; monoethanolamine; triethylamine;isopropanolamine; diethanolamine; and triethanolamine. When utilized,the pH modifier may be present in any effective amount needed to achievethe desired pH level.

To better enhance the benefits to consumers, other optional ingredientsmay also be used. For instance, some classes of ingredients that may beused include, but are not limited to: antioxidants (product integrity);anti-reddening agents, such as aloe extract; astringents--cosmetic(induce a tightening or tingling sensation on skin); colorants (impartcolor to the product); deodorants (reduce or eliminate unpleasant odorand protect against the formation of malodor on body surfaces);fragrances (consumer appeal); opacifiers (reduce the clarity ortransparent appearance of the product); skin conditioning agents; skinexfoliating agents (ingredients that increase the rate of skin cellturnover such as alpha hydroxy acids and beta hydroxyacids); skinprotectants (a drug product which protects injured or exposed skin ormucous membrane surface from harmful or annoying stimuli); andthickeners (to increase the viscosity of the composition).

Prior to use, the wipe is contacted with a sufficient amount ofgermicidal solution to disinfectant or sanitize a surface. As the wipeis rubbed on the surface, it releases the germicidal solution, whichcontacts bacteria present thereon. The wipe can also provide an abrasiveaction and a reabsorption capability to remove contaminants from thesurface. After use, the wipe can be disposed. The germicidal solutionmay remain on the surface to help kill and/or inhibit the growth ofbacteria thereon for a certain period of time. Although the amount ofantimicrobial agent released from the wipe in the present invention mayvary depending on the nature of the antimicrobial agent and/or othersolution components, it is typically present in an amount less thanabout 2000 parts per million (ppm) of the germicidal solution releasedfrom the wipe. In some embodiments, for example, a quaternary ammoniumhalide antimicrobial agent, as described in more detail above, can bepresent in the released germicidal solution in an amount less than about500 ppm, and in some embodiments from about 150 ppm to about 400 ppm ofthe released solution. Again, even when present in the releasedgermicidal solution in such small amounts, the desired level ofantimicrobial efficacy can still be achieved.

The wipe of the present invention may kill and/or inhibit (e.g., reduceby a measurable amount or to prevent entirely) the growth of one or moremicroorganisms when exposed thereof. Examples of microorganisms that maybe inhibited include bacteria (including cyanobacteria andMycobacteria), protozoa, algae, fungi (e.g., molds and yeast), viruses,prions, and other infectious particles. For example, the coating mayinhibit the growth of several medically significant bacterial groups,such as Gram negative rods (e.g., Entereobacteria); Gram negative curvedrods (e.g., Heliobacter, Campylobacter, etc.); Gram negative cocci(e.g., Neisseria); Gram positive rods (e.g., Bacillus, Clostridium,etc.); Gram positive cocci (e.g., Staphylococcus, Streptococcus, etc.);obligate intracellular parasites (e.g,. Ricckettsia and Chlamydia); acidfast rods (e.g., Myobacterium, Nocardia, etc.); spirochetes (e.g.,Treponema, Borellia, etc.); and mycoplasmas (i.e., bacteria that lack acell wall). Particularly species of bacteria that may be inhibited withthe composition of the present invention include Escherichia coli (Gramnegative rod), Klebsiella pneumonia (Gram negative rod), Streptococcus(Gram positive cocci), Salmonella choleraesuis (Gram negative rod),Staphyloccus aureus (Gram positive cocci), and P. aeruginosa (Gramnegative rod). In addition to bacteria, other microorganisms of interestinclude fungi (e.g., Aspergillus niger) and yeasts (e.g., Candidaalbicans).

Upon exposure for a certain period of time, the wipe may provide a logreduction of at least about 2, in some embodiments at least about 3, insome embodiments at least about 4, and in some embodiments, at leastabout 5 (e.g., about 6). Log reduction, for example, may be determinedfrom the % population killed by the composition according to thefollowing correlations:

% Reduction Log Reduction 90 1 99 2 99.9 3 99.99 4 99.999 5 99.9999 6

Such a log reduction may be achieved in accordance with the presentinvention after only a relatively short exposure time. For example, thedesired log reduction may be achieved after exposure for only 30minutes, in some embodiments 15 minutes, in some embodiments 10 minutes,in some embodiments 5 minutes, and in some embodiments, 1 minute.

As discussed above, it has also been discovered that the selection andrelative amounts of the components of the polymer coating on the wipecan allow control over the amount of antimicrobial agent absorbed intothe wipe and not released during use. This phenomenon can be quantifiedby the antimicrobial “Release Value” according to the formula below:100×[Q _(r) /Q _(i)]

wherein, Q_(i) is the amount of antimicrobial agent added to thegermicidal solution, and Q_(r) is the amount of antimicrobial agentreleased as a solution released from the wipe. In most embodiments ofthe present invention, the “Release Value” is about 80% or more, in someembodiments about 85% or more, in some embodiments about 90% or more,and in some embodiments, from about 95% to about 99%.

The present invention may be better understood with reference to thefollowing examples.

EXAMPLE 1

An uncoated fibrous web was tested for its quaternary amine releaseproperties. The tested fabric was WYPALL®X70, a HYDROKNIT™ materialavailable from Kimberly-Clark® Professional. The web had an averagebasis weight of 82 grams per meter squared (gsm) and contained pulpfibers hydroentangled into a polypropylene spunbond web having a basisweight of approximately 1 gsm. The quaternary amine was Oasis® 146 fromECOLAB®, Inc., and it was mixed to a 400 ppm of total quaternary amine.Oasis® 146 contains 3% of alkyl C₁₄ 50%, C₁₂ 40%, C₁₆ 10% dimethylbenzyl ammonium chloride, 2.25% of octyl benzyl ammonium chloride, 1.35%didecyl dimethyl ammonium chloride, 0.9% dioctyl dimethyl ammoniumchloride, and q.s. water. The fabric was tested using the followingprocedure:

-   -   Mix 1 liter of the Oasis® 146 at 400 ppm in a large one liter        beaker.    -   Collect initial sample of the mixed Oasis® 146 for base line        concentration.    -   Cut 2 to 3 wipes (specimens) to an appropriate size to achieve        approximately 1 gram wipe for 67 grams of solution.    -   Weigh both wipes and record weight.    -   Place both wipes into the one liter solution.    -   At 15 minutes, remove both wipes and squeeze excess liquid from        wipes back into the beaker. Then squeeze extract from wipes into        labeled vial for submission to for analytical testing.

The extracted sanitizer, as well as the initial Oasis® 146, was testedfor quaternary amine concentration using High Pressure LiquidChromatography (HPLC) under the following conditions and using thefollowing procedures:

Preparation of Reagents and Stock Standard Solutions

0.1% Formic Acid

Add 900 ml of Milli-Q water to a 1000 ml volumetric flask. Pipet 1.0 mlof formic acid (EMD FX0440-11) to the flask and dilute to volume withMilli-Q water. Use as prepared.

0.1% Trifluoroacetic Acid (TFA)

Add 900 ml of Milli-Q water to a 1000 ml volumetric flask. Add oneampoule of TFA (J T Baker 9470-00-10×1 ml ampoules) to the flask anddilute to volume with Milli-Q water. Use as prepared.

Preparation of Stock Standard

Weigh accurately 0.14 grams of the Oasis® 146 (7.5% active) concentratedsolution into a 10.0 ml volumetric flask. Dilute to volume with Mill-Qwater and shake.

Calibration Standards

Calibration standard aliquots were measured with a 100 μl or a 500 μlHamilton Gastight® #1750 syringe. Milli-Q water was added to theautosampler vials with a 1000 μl Hamilton Gastight® #1001 syringe.Aliquots of 100, 200, 300, 400, 500 and 700 μls were taken from theOasis 146 stock standard solution and transferred to six 2 mlautosampler vials and labeled 1 to 6. The vials were diluted to 1000 μlwith 900, 800, 700, 600, 500, and 300 μls of Milli-Q water,respectively, to prepare Oasis® 146 calibration standards.

Chromatographic Conditions—Quat Analysis

-   -   System: Agilent Series 1100 Quaternary HPLC    -   Column: Sielc Primesep B2 5μ 100 Å (2.1×100 mm) Part        #B2-21.100.0510    -   Col Temp: 45° C.    -   Detector 1: PL-ELS 2100 (Evaporative Light Scattering Detector)    -   Evap Temp: 45° C.    -   Neb Temp: 35° C.    -   Gas Flow: 1.5 SLM nitrogen gas    -   Gain: 10×    -   Detector 2: Agilent Series 1100 Diode Array    -   Sig/Bandwth: 254 nm/4 nm    -   Ref/Bandwth: 360 nm/10 nm    -   Gradient: A—0.1% formic acid        -   B—acetonitrile        -   0 min: 70% A/30% B        -   5.0 min: 40% A160% B        -   5.1 min: 70% A/30% B    -   Flow rate: 0.8 ml/min    -   Injection vol: 10 μl    -   Elution Time: DODMAC—0.98 min        -   C₁₂ DMBAC—1.3 min (approx.)        -   ODDMAC—1.7 min        -   C₁₄ DMBAC—2.4 min        -   DDDMAC—2.7 min        -   C₁₆ DMBAC—3.3 min

The standard concentrations were corrected for their actual percentagein the quaternary amine solution. The % quaternary amine (quats) releaseresults (i.e., Release Values) were based on the amount of expressedquats recovered relative to the prepared Oasis Control solution. ForExample 1, the Quat Release Value was determined to be 58%.

EXAMPLE 2

The WYPALL®X70 sheet of Example 1 was coated with Polymin® SK (BASF) toa target add-on of 0.75% using the following “dip and squeeze” method:

-   -   Cut fibrous web samples into desired shape and size, and weigh        sample.    -   Recorded dry sample weight.    -   Mix treatment bath using distilled and ionized water. Let bath        come to room temperature.    -   Mix bath to a % active concentration to a target wet pick-up and        target % by weight add-on.    -   Dip web/fabric sample into bath and squeeze out excess fluid by        running the sample through an Atlas Laboratory Wringer.        Alternatively, if the samples are small enough, they could be        squeezed by hand.    -   Weight sample to verify targeted wet pick-up. Wet pick-up=(wet        weight−dry weight/wet weight)*100.    -   If sample is not at target wet pick-up adjust lab wringer        pressure or remake treatment bath at new wet pick-up target.    -   If wet pick-up is correct, hang wet fabric sample in oven and        dry for 45 minutes at 90° C.    -   Let samples rehydrate over night and reweight sample.    -   Add-on level is calculated by (final weight−initial        weight/initial weight)*100=% add-on.    -   If add-on level is not on target adjust bath and remake the        sample.    -   Depending on the level of accuracy required, the actual data        should be within 25% of the targeted add-on.

The finished wipes were soaked in a quaternary amine solution and thesolution was expressed out of the wipe after 15 minutes as described inExample 1. The quaternary amine solution used was Oasis® 146 fromECOLAB® and was mixed to a 400 ppm of total quaternary amine. Theexpressed solution was tested for quaternary amine release using thesame HPLC method as described in Example 1. The Quat Release Value wasdetermined to be 89.8%. Furthermore, the expressed solution was testedfor efficacy with gram negative bacterial using ASTM E2315-03 withEscherichia coil (E. coli) as the test organism. The percent reductionof E. coli after 1 minute of exposure was 99.999%.

EXAMPLE 3

A sample was formed as described in Example 2, except that the Polymin®SK had a target add-on level of 1.0% by weight. The Quat Release Valuewas determined to be 94.5% and the percent reduction of E. coli after 1minute of exposure was 99.738%.

EXAMPLE 4

A sample was formed as described in Example 2, except that the Polymin®SK had a target add-on level of 1.5% by weight. The Quat Release Valuewas determined to be 96.3% and the percent reduction of E. coli after 1minute of exposure was 89.458%.

EXAMPLE 5

A sample was formed as described in Example 2, except that the Polymin®SK had a target add-on level of 2.0% by weight. The Quat Release Valuewas determined to be 99.7% and the percent reduction of E. coli after 1minute of exposure was 99.264%.

EXAMPLE 6

A sample was formed as described in Example 2, except that the Polymin®SK had a target add-on level of 3.0% by weight. For this Example, thefabric was not coated using a “hand” dip and squeeze method, but wasinstead coated using a continuous dip and squeeze method and subsequentinline impingement oven. The line speed was 23 feet per minute and themaximum dryer temperature was set at 360° F. The Quat Release Value wasdetermined to be 100% and the percent reduction of E. coli after 1minute of exposure was 76.58%.

EXAMPLE 7

A sample was formed as described in Example 2, except that the polymerwas Polymin® P (BASF) and the target add-on level was 2.0% by weight.The Quat Release Value was determined to be 77.2% and the percentreduction of E. coli after 1 minute of exposure was 99.999%.

EXAMPLE 8

A sample was formed as described in Example 7, except that the targetadd-on level was 3.0% by weight. The Quat Release Value was determinedto be 84% and the percent reduction of E. coli after 1 minute ofexposure was 99.999%.

EXAMPLE 9

A sample was formed as described in Example 7, except that the targetadd-on level was 5.0% by weight. The Quat Release Value was determinedto be 87% and the percent reduction of E. coli after 1 minute ofexposure was 99.999%.

EXAMPLE 10

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 0.25%by weight and Polymin® P at an add-on level of 5.0% by weight. The QuatRelease Value was determined to be 91.7% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLE 11

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 0.5%by weight and Polymin® P at an add-on level of 3.0% by weight. The QuatRelease Value was determined to be 92.9% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLE 12

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 0.5%by weight and Polymin® P at an add-on level of 2.5% by weight. The QuatRelease Value was determined to be 86.9% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLE 13

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 0.75%by weight and Polymin® P at an add-on level of 3.0% by weight. The QuatRelease Value was determined to be 99.5% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLE 14

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 0.75%by weight and Polymin® P at an add-on level of 5.0% by weight. The QuatRelease Value was determined to be 92.1% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLE 15

A sample was formed as described in Example 2, except that the coatingcontained a combination of Polymin® SK at a target add-on level of 1.0%by weight and Polymin® P at an add-on level of 2.0% by weight. The QuatRelease Value was determined to be 95.0% and the percent reduction of E.coli after 1 minute of exposure was 99.999%.

EXAMPLES 16-23

Solution samples were formed by mixing an Oasis® 146 sanitizing solutionto 400 ppm, and thereafter adding a certain concentration of Polymin® SK(BASF), Polymin® P (BASF), poly(ethyleneimine) (Sigma-Aldrich), and/orethylenediaminetetraacetic acid disodium salt (EDTA, Sigma-Aldrich). Thepoly(ethyleneimine) (“PEI”) from Sigma-Aldrich (catalog #P3143) had aweight average molecular weight of 750,000 grams per mole. The sampleswere tested for efficacy using ASTM E2315-03 for E. coli as the testorganism. The results are set forth in the Table below:

% Reduction Oasis ® E. coli after 1 146 Polymin ® Polymin ® P PEI EDTAminute Example (ppm) SK (ppm) (ppm) (ppm) (ppm) exposure 16 400 0 0 0 099.999% 17 400 100 0 0 0 99.976% 18 400 500 0 0 0 95.743% 19 400 1000 00 0 93.999% 20 400 0 1000 0 0 99.999% 21 400 500 500 0 0 99.999% 22 4000 0 1000 0 99.999% 23 400 1000 0 0 1000 65.387%

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

What is claimed is:
 1. A wipe for use with a germicidal solution,wherein the wipe comprises a fibrous substrate impregnated with agermicidal solution containing an anti-microbial quaternary ammoniumcompound and further comprises a polymer coating disposed onto thefibrous substrate, the polymer coating containing a release agent and acell permeabilizer, wherein the release agent includes a crosslinkedpolyamideamine and the cell permeabilizer includes a polycationicsubstance, wherein the crosslinked polyamideamine has a weight averagemolecular weight of about 1,000,000 to about 2,000,000 grams per moleand the polycationic substance has a weight average molecular weight ofabout 600,000 to about 1,000,000 grams per mol, and wherein the ratio ofthe weight average molecular weight of the crosslinked polyamideamine tothe weight average molecular weight of the polycationic substance isgreater than 1 to about
 3. 2. The wipe of claim 1, wherein thepolyamideamine is formed from a polyalkylenepolyamine prepolymer.
 3. Thewipe of claim 2, wherein the polyalkylenepolyamine is polyethyleneimine.4. The wipe of claim 2, wherein the polyalkylenepolyamine is a polyaminethat is grafted with ethyleneimine.
 5. The wipe of claim 2, wherein theprepolymer is crosslinked with a polyfunctional crosslinking agent. 6.The wipe of claim 5, wherein the crosslinking agent includes amonoethylenically unsaturated carboxylic acid, or an ester, amide, oranhydride thereof.
 7. The wipe of claim 1, wherein the polyamideamine isalkoxylated.
 8. The wipe of claim 1, wherein the ratio of the weightaverage molecular weight of the crosslinked polyamideamine to the weightaverage molecular weight of the polycationic substance is from about 1.2to about 1.8.
 9. The wipe of claim 1, wherein the polycationic substanceis a polyamine.
 10. The wipe of claim 9, wherein the polyamine is acrosslinked polyamideamine.
 11. The wipe of claim 1, wherein the weightratio of the cell permeabilizer to the release agent is from about 2 toabout
 10. 12. The wipe of claim 1, wherein the cell permeabilizerconstitutes from about 60 wt. % to about 95 wt. % of the coating and therelease agent constitutes from about 5 wt. % to about 40 wt. % of thecoating.
 13. The wipe of claim 1, wherein the solids add-on level of thepolymer coating is from about 0.5% to about 15%.
 14. The wipe of claim1, wherein the fibrous substrate contains absorbent fibers.
 15. The wipeof claim 14, wherein the absorbent fibers include cellulosic fibers. 16.The wipe of claim 15, wherein the cellulosic fibers include pulp fibers.17. The wipe of claim 14, wherein the fibrous substrate is a compositethat contains the absorbent fibers and synthetic thermoplastic fibers.18. A method for disinfecting a surface, the method comprisingcontacting the surface with a wipe impregnated with a germicidalsolution so that the solution is expressed therefrom, wherein thegermicidal solution comprises an antimicrobial quaternary ammoniumcompound, and wherein the wipe comprises a fibrous substrate on which isdisposed a polymer coating, the polymer coating containing a releaseagent and a cell permeabilizer, wherein the release agent includes acrosslinked polyamideamine and the cell permeabilizer includes apolycationic substance, wherein the crosslinked polyamideamine has aweight average molecular weight of about 1,000,000 to about 2,000,000grams per mole and the polycationic substance has a weight averagemolecular weight of about 600,000 to about 1,000,000 grams per mol, andwherein the ratio of the weight average molecular weight of thecrosslinked polyamideamine to the weight average molecular weight of thepolycationic substance is greater than 1 to about
 3. 19. The method ofclaim 18, wherein the polyamideamine is formed from apolyalkylenepolyamine prepolymer.
 20. The method of claim 18, whereinthe polyalkylenepolyamine is polyethyleneimine, a polyamine that isgrafted with ethyleneimine, or a combination thereof.
 21. The method ofclaim 18, wherein the ratio of the weight average molecular weight ofthe crosslinked polyamideamine to the weight average molecular weight ofthe polycationic substance is from about 1.2 to about 1.8.
 22. Themethod of claim 18, wherein the polycationic substance is a polyamine.23. The method of claim 18, wherein the fibrous substrate containsabsorbent fibers.
 24. The method of claim 18, wherein about 90% or moreof the antimicrobial agent added to the germicidal solution is expressedfrom the wipe.
 25. The method of claim 18, wherein the wipe provides alog reduction of at least about 4 for a gram negative bacteria.
 26. Themethod of claim 25, wherein the gram negative bacteria is E.Coli.